1. Technical Field
The present invention relates to an occupant protection apparatus for a vehicle such as an automobile.
2. Related Art
An occupant protection apparatus for a vehicle is disclosed in, for instance, Japanese Unexamined Patent Application Publication (JP-A) No. 2000-247199. According to the occupant protection apparatus of JP-A No. 2000-247199, a passenger-side airbag mounted on top of a dashboard is deployed in front of a front passenger seat. In the event of a head-on crash where the front ends of two vehicles collide with each other in opposite directions, an occupant seated in the passenger seat falls forward and plunges into the deployed passenger-side airbag. The passenger-side airbag is capable of supporting the head and upper body of the falling-forward occupant.
However, not all vehicles collide head-on with each other. For instance, vehicles may be subjected to a frontal oblique collision with each other.
When a vehicle equipped with the occupant protection apparatus (“subject vehicle”) may be collided by another vehicle from an oblique front on the side of the driver's seat, the occupant seated in the passenger seat of the subject vehicle falls forward while falling toward the longitudinal centerline side of the vehicle. In this case, the head and upper body of the falling-forward occupant may drop toward the longitudinal centerline side of the deployed passenger-side airbag.
To prevent the occupant from dropping, it is conceivable that a deployment area of the passenger-side airbag is expanded to the longitudinal centerline side or that a sub-bag is projected from the thus expanded area to the rear of the vehicle.
However, only expanding the deployment area of the passenger-side airbag to the longitudinal centerline side makes it difficult to properly support the occupant who is plunging into the airbag while being inclined toward the longitudinal centerline side.
Specifically, when the occupant seated in the passenger seat plunges into the passenger-side airbag while being inclined toward the longitudinal centerline side, the load of the occupant is exerted on an end of the passenger-side airbag on the longitudinal centerline side. The load of the occupant acts as a force directed obliquely forward on the longitudinal centerline side so as to move away from the passenger-side airbag. For this reason, the passenger-side airbag that is deployed toward the longitudinal centerline side tends to fall toward the longitudinal centerline side due to the load of the occupant. As a result, the head and upper body of the occupant that is initially supported by the passenger-side airbag may drop on the longitudinal centerline side of the passenger-side airbag since the passenger-side airbag becomes inclined toward the longitudinal centerline side.